what is crude oil
a mixture of different hydrocarbons of similar chain length called fractions
how do the physical properties of hydrocarbons change as the molecule size increases
boiling point increases
liquid becomes less volatile, more viscous and darker
don’t burn as easily
why do the physical properties of hydrocarbons change as the molecule size increases
increasing attraction between molecules
more energy needed to break intermolecular forces
how are the fractions in crude oil separated
by fractional distillation
does the number of carbon atoms in a chain affect properties and boiling points
yes
what is the determining factor for fractional distillation
size and length of each hydrocarbon molecule
what does the size of each hydrocarbon molecule depend on
number of carbon and hydrogen atoms the molecule contains
fractional distillation
crude oil is heated and vapour is passed into a fractionating column
the vapour rises up depending on its boiling point
positioning of crude oil in a fractionating column
cool at the top and hot at the bottom
do smaller molecules have lower boiling points or higher
lower
do larger molecules have lower boiling points or higher
higher
what are the different heights that the different fractions condense at dependent on
their boiling points
order of main fractions from coolest to hottest
refinery gas
gasoline
kerosene
diesel oil
fuel oil
bitumen
what is refinery gas
a mixture of methane, ethane, propane, butane
uses of refinery gas
used for LPG for domestic heating and cooking
uses of gasoline
fuel in cars
uses of kerosene
fuel for jet aircrafts, domestic heating oil and paraffin
uses of diesel
fuel for buses, lorries, cars, railway engines and conversion into petrol for cracking
uses of fuel oil
fuel for ships and industrial heating
uses of bitumen
melted and mixed with small pieces of rock to make the top surface of roads
what is a fuel
a substance which when burnt releases heat energy
fossil fuels
coal
oil
natural gas
oil shales
tar sands
how are non-renewable fossil fuels obtained
from fractional distillation in crude oil
combustion - products
carbon dioxide
carbon monoxide
oxides of nitrogen
oxides of sulfur
unburned hydrocarbons
carbon particulates
complete combustion in hydrocarbon compounds
occurs in the presence of excess oxygen
a hydrocarbon burns in air to form carbon dioxide and water
it also releases heat
incomplete combustion in hydrocarbon compounds
occurs in presence of insufficient oxygen
it releases soot, carbon monoxide and water
carbon monoxide
toxic and odourless gas causing death
what are the dangers of carbon monoxide
it reduces the ability of the blood to carry oxygen around the body by binding to haemoglobin
how is carbon dioxide harmful for the environment
it’s a greenhouse gas which traps heat radiated from the earth’s surface
what is formed when nitrogen and oxygen react in the high pressure and temperature conditions of internal combustion engines and blast furnaces
NO and NO2
acid rain
formed when water and oxygen in the atmosphere react with sulfur dioxide to product sulfuric acid, or various nitrogen oxides to give nitric acid
how do fossil fuels contribute to acid rain
they contain a small amount of sulfur which is burned with the fuel and forms sulfur dioxide
this reacts in the atmosphere with oxygen and water and becomes sulfuric acid
nitrogen dioxide from car engine reacts with rain water to form nitrous and nitric acids